In general, an electric motor is an apparatus which convents an electrical energy into a mechanical energy using a force applied to a conductor flowing a current in a magnetic field, and is typically referred to as a motor. The motor is classified into a direct current (DC) motor and an alternating current (AC) motor according to types of power source, and the AC motor is again classified into a three-phase AC motor and a single-phase AC motor. Currently, the three-phase AC motor is mainly used.
The motor began to be made since around the time that Faraday discovered electromagnetic induction in 1831. The initial method of operating the motor is that a moving part was oscillated without rotating the same using the attraction and repulsion of permanent magnets. In the 1830s, a DC motor like today's type was first made using an armature and DC excited electromagnets, but the output was small and it was only developed in the research phase.
Thereafter, with Ferraris and Tesla's discovery of a rotating magnetic field being generated in an alternating current, they independently invented a two-phase AC motor. Since Dobrowolski from Germany first made a three-phase AC motor having an output of 100 watts (W), the three-phase AC motor has been mainly used as today's AC motor.
Both of the DC motor and AC motor are operated on the same principle. When placing a conductor flowing a current in the magnetic field, an electromagnetic force (Lorentz force) is generated in a direction perpendicular to the direction of the magnetic field. When placing the magnet inside the motor, a magnetic field is generated, and if the current flows in a conducting wire connected to a shaft, an electromagnetic force is generated. Accordingly, the shaft rotates to generate power according to the Fleming's left-hand rule. The electromagnetic force acting on the conducting wire is proportional to an intensity of the magnetic field, an intensity of the current and a length of the conducting wire.
The most typical motor based on the above-described principle has a universal and basic configuration in which a rotor including the permanent magnet or electromagnet is installed inside a stator including the permanent magnet or electromagnet. In particular, in a case of a DC motor having four contacts, the rotor including the electromagnet receives the power through the contacts to generate a continuous rotating motion through the attraction and repulsion by electromagnetism.
Generally, since when increasing a speed of the electric motor, a driving force is reduced, it is necessary for the electric motor to further include a reduction gear in order to obtain a desired driving force. However, if adding the reduction gear to the motor, the speed thereof is reduced. For an automobile, the above-described problem is solved by using a power of 300 volts or more, but the efficiency of the motor is significantly degraded due to rapid battery drainage, and an increase in a weight and costs of the vehicle.
Meanwhile, Korean Patent Registration Nos 10-1025387 and 10-1117044, which are filed by and issued to the present applicant, disclose a high-efficiency disc rotating apparatus for power generation and transfer, and Korean Patent Laid-Open Publication No. 10-2011-0064759 discloses a wheel having a means for power generation and transfer. These patents solve the problems entailed in the conventional electric motors by utilization of a special environment.
However, in the above-described electric motors, a predetermined driving force and a predetermined rotational force due to a turn ratio of a coil are always generated. Even when applying the above-described electric motor, in order to provide an increased driving force, a separate auxiliary power unit should be added thereto, and it is necessary to secure an installation space, which results in a large increase in costs. In addition, when increasing the driving force by adding the reduction gear, there is a limit to obtain the driving force by one driving apparatus.
Further, excessive power for driving the auxiliary power should be used, and thereby, the efficiency thereof is significantly degraded due to the consumption of a lot of power.